After finding out that accessing SMB shares is not possible with lates OSX and RB 751G-2HnD cause old SMB version is used that is not supported any more by OSX. Worked flawlessly on windows 
I thought that if router supports ssh I could mount the external usb hdd attached to router or a share with SSHFS and gave it a go:
- mounts the drive and I can browse and open files no issues here
sshfs admin@192.168.88.1:/ -p 2234 /tmp/ssh -ocache=no -onolocalcaches -ovolname=ssh -o defer_permissions
- can’t write any files as trying to move anything to mounted fs (either to external or internal folders) fails with
"Items can’t be copied to “testfolder” because you don’t have permission to read them.
Anyone ever tried to do so and had any luck on writing files to external hdd like that?